After applying a patch that moves a bulk of code that was placed in a wrong file to its correct place, a quick way to sanity-check that the patch does not introduce anything unexpected is to run "git blame -C -M" between HEAD^ and HEAD, like this:
$ git blame -C -M HEAD^..HEAD -- new-location.c
This should show that the lines moved from the old location in the output as coming from there; lines blamed for the new commit (i.e. not coming from the old location) can then be inspected more carefully to see if it makes sense.
One problem I had while doing exactly that today was that most of the screen real-estate on my 92-column wide terminal was taken by the author name and the timestamp, and I found myself pressing right and left arrow in my pager to scroll horizontally a lot, which was both frustrating and suboptimal.
$ git blame -h
told me that there is "git blame -s" to omit that information. I thought that I didn't know about the option. Running "git blame" on its source itself revealed that the option was added by me 8 years ago, and it wasn't that I didn't know but I simply forgot ;-)